A U.S. Pat. No. 3,745,631 issued on July 17, 1973 for a "Method and Apparatus for Manufacturing Finned Heat Exchangers." The subject matter of this application constitutes an improvement on the method and apparatus disclosed in this patent.
U.S. Pat. No. 3,745,631 teaches a method and apparatus for producing heat exchanger elements of the type which comprise corrugated surface enlarging members of strip material fixed to a thin wall substrate, sometimes called a basic profile. The strip material, which can be either pre-corrugated or corrugated just prior to its use, is advanced concurrently with the basic profile to a station at which the strip is lightly held in firm abutment with the basic profile by means of an impinging stream of a gaseous medium, and is simultaneously metallurgically bonded to the substrate. The composite product is then cut into lengths to form finished heat exchanger elements.
In accordance with the teachings of U.S. Pat. No.3,745,631 a preheat furnace or melt zone 15 is provided to heat the basic profile prior to the time at which the basic profile is metallurgically bonded to the corrugated strip material. While not so stated in the patent, the company selling these machines has made the preheating furnace construction one in which an inert gas such as nitrogen is used as a protective atmosphere during heating.
In order to maintain the inert atmosphere within the preheat furnace 15, an elaborate system is necessary for introducing the basic profile and then removing the same from the preheat furnace so that the inert gases are not permitted to escape therefrom. Such an elaborate system is very costly and, of course, adds to the cost of the overall process and apparatus.
It is a principal object of this invention to provide a process and apparatus for heating the various elements which are to be metallurgically bonded in a manner which is more efficient and less costly than that devised and shown in the 3,745,631 patent.
A U.S. Pat. No. 2,684,425 issued on July 20, 1954 for an "Induction Brazing Jig." This patent shows a brazing jig assembly for assembling heat exchanger envelopes in which metallurgical bonds are formed between various components in order to form a completed heat exchange envelope. The patent shows the use of an electric induction heating coil 52 positioned adjacent the members to be bonded. This heating coil is positioned so as to completely embrace the envelope assembly as it is drawn through the coil. The coil is used to heat the materials passing therethrough in order to obtain the required metallurgical bond by a brazing action between the various components.